What Scientists Learned From 'Investigating' 61 Public Bathrooms

What Scientists Learned From 'Investigating' 61 Public Bathrooms
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Two scientists have made a brave sacrifice in the name of public health.

M. C. Jeffrey Lee of National Taichung University of Science and Technology in Taiwan and K. W. Tham of the National University of Singapore thoroughly “investigated” 61 public toilets in Taiwan to identify potential biological hazards.

They documented their sanitation adventure in a paper just published to the journal Scientific Reports.

As Lee and Tham reminded readers, the flushing toilet is one of the greatest public health advances of all time. However, public bathrooms can spread infectious disease if not designed, maintained, and used properly. Urine and feces not adequately disposed of can quickly become a breeding ground for noxious bacteria.

With this in mind, the duo set out to measure bacterial counts on surfaces and in the air of 61 frequently used public bathrooms in a large city in Taiwan. These were located in shopping malls, hospitals, offices, libraries, and train stations. Lee and Tham swabbed for microbes in toilet bowls, on urinal rims, and on adjacent floors, among many other locations. They also sampled the air with bio-aerosol impactors.

Lee and Tham found that toilet and urinal bowls were generally pretty clean – after all, "bacteria can be swept away with a flush," they wrote. However, the lining between the toilet and the floor, and the floor itself around the toilet or urinal was highly contaminated with potentially disease-causing bacteria.

Lee & Tham / Scientific Reports

The duo also discovered that ventilation in bathrooms can make a big difference in terms of airborne bacterial counts.

"The bacterial contamination (CFUs) cultured from the indoor samples collected from ventilation-equipped public toilets were lower than outdoor levels (CFUs). In contrast, the CFUs of indoor samples from public toilets without ventilation were between 1.5 and 5 times higher than the CFUs of outdoor samples. If the carriers entered those public toilets, the viruses produced by the carriers could persist in the exhaled aerosols, in the flushing fluid (potentially containing fragments of excreta) splashed onto the floor or the bio-waste from lid-less trash cans."

Lee & Tham / Scientific Reports

To counter the possibility of disease spread from public bathrooms, Lee and Tham recommend that the problem areas they identified be cleaned frequently with proper disinfecting agents. Bathrooms should also be sufficiently ventilated. Ultraviolet-C lights could also be utilized to cleanse surfaces when bathrooms are unoccupied.

Source: Lee, M.C.J., Tham, K.W. Public toilets with insufficient ventilation present high cross infection risk. Sci Rep 11, 20623 (2021). https://doi.org/10.1038/s41598-021-00166-0

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